High pressure ratio compressors with multiple intercooling and related methods

ABSTRACT

Turbo-compressor/generator trains including high pressure ratio compressors with multiple intercooling and related methods are provided. A high pressure ratio compressor with multiple intercooling includes a casing with plural chambers, one or more shafts penetrating inside the chambers, and impellers mounted on the one or more shafts inside the chambers, respectively. Each chamber has a gas inlet and a gas outlet to allow gas flow to be input into and to be output from the respective chamber. A gas flow is successively compressed in each of the chambers, and is cooled outside the compressor when transferring from one chamber to a next chamber among the plural chambers.

BACKGROUND

Embodiments of the subject matter disclosed herein generally relate tohigh pressure ratio compressors with multiple intercooling and relatedmethods; more particularly, to a turbo-compressor/generator train usinga high pressure compressor with multiple intercooling instead of pluralcompressors.

One type of turbo-machinery is a centrifugal compressor. Centrifugalcompressors are usually designed in families intended to cover aspecific flow range and use. In order to achieve a desired compressionratio, a centrifugal compressor may be arranged to perform compressionone after another. For example, two centrifugal compressors aretypically arranged in a turbo-compressor/generator train 100 asillustrated in FIG. 1. Such turbo-compressor/generator trains may beused for blast furnaces in the steel industry, natural gas liquefaction,gas reinjection and other oil and gas services.

Five machines are mechanically coupled in the turbo-compressor/generatortrain 100: a gas turbine 110, a generator 120, a gear box 130, a firstlow pressure compressor 140, and a second compressor 150. This type ofarrangement is sometimes called a “single-shaft” configuration.

The generator 120 may have a rotation speed of 3000 rotations per minute(RPM). The gear box 130 is a step-up type of gear, for example,increasing the rotation speed to 5000 RPM and transmitting this rotationto the first compressor 140 and to the second compressor 150.

The first low pressure compressor 140 may be of a double flow typereceiving via two inputs the gas flow at an input pressure (e.g., ofabout 0.97 bar) and an input temperature (e.g., of about 41.5° C.), andoutputting the gas flow at an output pressure (e.g., of about 3.20 bar)and an output temperature (e.g., of about 187° C.). The output gas isthen cooled and input to the second compressor 150.

The second compressor 150 may be a two-section type of compressorreceiving first an input gas flow at a first input pressure (e.g., 2.85bar) and a first input temperature (e.g., of about 40° C.) andoutputting a first output flow at a first output pressure (e.g., ofabout 7.90 bar) and a first output temperature (e.g., of about 160° C.).This first output flow is then cooled and input to the compressor 150 asa second flow at a second input pressure (e.g., 7.50 bar) and a secondinput temperature (e.g., of about 40° C.). The compressor 150 thenoutputs a second output flow at a second output pressure (e.g., of about20.8 bar) and a second output temperature (e.g., of about 166° C.).

Note that the second input pressure is slightly lower than the firstoutput pressure, and the third input pressure is slightly lower than thesecond output pressure. Also, the gas flow may be about 22-230000 kg/h,but flow losses of around 10% may occur during cooling.

In the conventional turbo-compressor/generator train, the compressor hasclosed and shrunk fit impellers, the required compression being achievedby splitting the compression process into sub-processes performed insidethe two different compressors. Reliability is sub-optimal due to the useof the two different compressors and the transition there-between.Additionally, the cost of the two compressors and the operating costs(footprint) thereof make it attractive to seek using more efficient,cheaper and reliable equipment for the compression.

Accordingly, it would be desirable to provide a high pressure compressorwith multiple intercooling and related methods that avoid theafore-described problems and drawbacks.

BRIEF DESCRIPTION OF THE INVENTION

The use of a high pressure air compressor with two levels ofintercooling instead of two compressors in a turbo-compressor/generatortrain allows removal of one large casing, leading to a benefit in size,cost, overall reliability and footprint.

According to one exemplary embodiment, a high pressure ratio compressorwith multiple intercooling used in a turbo-compressor/generator trainincludes a casing with plural chambers, one or more shafts penetratinginside the chambers, and impellers mounted on the one or more shafts,inside the chambers, respectively. Each chamber has a gas inlet and agas outlet to allow gas flow to be input into and to be output from therespective chambers. A gas flow is successively compressed in each ofthe chambers, and is cooled outside the compressor when transferringfrom one chamber to the next chamber among the plural chambers.

According to another embodiment, a turbo-compressor/generator trainincludes a high pressure ratio compressor with multiple intercooling.The compressor has a casing with plural chambers, one or more shaftspenetrating inside the chambers, and impellers mounted on the one ormore shafts, inside the chambers, respectively. Each chamber has a gasinlet and a gas outlet to allow gas flow to be input into and to beoutput from the respective chambers. The gas flow is successivelycompressed in each of the chambers, and is cooled outside the compressorwhen transferring from one chamber to the next chamber among the pluralchambers.

According to another exemplary embodiment, a method of retrofitting aconventional turbo-compressor/generator train includes (A) removing atleast two compressors from the conventional turbo-compressor/generatortrain, and (B) adding a single high pressure ratio compressor withmultiple intercooling. The single compressor is configured to achievethe same compression as the removed compressors.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate one or more embodiments and,together with the description, explain these embodiments. In thedrawings:

FIG. 1 is a schematic diagram of a conventionalturbo-compressor/generator train;

FIG. 2 is a schematic diagram of a turbo-compressor/generator train,according to an exemplary embodiment;

FIG. 3 is a schematic diagram of a turbo-compressor/generator train,according to another exemplary embodiment; and

FIG. 4 is a flowchart illustrating a method for retrofitting aconventional turbo-compressor/generator train, according to an exemplaryembodiment.

DETAILED DESCRIPTION OF THE INVENTION

The following description of the exemplary embodiments refers to theaccompanying drawings. The same reference numbers in different drawingsidentify the same or similar elements. The following detaileddescription does not limit the invention. Instead, the scope of theinvention is defined by the appended claims. The following embodimentsare discussed, for simplicity, with regard to the terminology andstructure of a turbo-compressor/generator train. However, theembodiments to be discussed next are not limited to these systems, butmay be applied to other systems in which plural compressors are used.

Reference throughout the specification to “one embodiment” or “anembodiment” means that a particular feature, structure or characteristicdescribed in connection with an embodiment is included in at least oneembodiment of the subject matter disclosed. Thus, the appearance of thephrases “in one embodiment” or “in an embodiment” in various placesthroughout the specification is not necessarily referring to the sameembodiment. Further, the particular features, structures orcharacteristics may be combined in any suitable manner in one or moreembodiments.

In some embodiments, plural impellers are mounted in the same one casingto achieve a more efficient, cheaper and reliable compressor capable ofperforming the duty of the two compressors in a conventionalturbo-compressor/generator train.

A schematic diagram of a turbo-compressor/generator train 200, accordingto an exemplary embodiment, is illustrated in FIG. 2. Theturbo-compressor/generator train 200 includes a gas turbine 210, agenerator 220, a gear box 230, and a single compressor 245 with multiplecooling. The gas turbine 210, the generator 220, and the gear box 230may be similar to the gas turbine 110, the generator 120, and the gearbox 130 in the conventional turbo-compressor/generator train 100.

The compressor 245 is a high pressure ratio compressor with multipleintercooling. The ratio of the output pressure (of the gas flow outputfrom the compressor 245 after being compressed) to the input pressure(of the gas flow input to the compressor 245 for being compressed) maybe over 20. Shafts 265 and 265′ of the compressor 245 are axiallyconnected and may be supported by plural bearings. In FIG. 2, a firstbearing 260 is located outside the casing 246 of the compressor 245, onthe shaft 265′ at a side of the casing 245 toward the gear box 230. Asecond bearing 270 is also located outside the casing 246, on the shaft265 at the opposite side of the casing 246 relative to the side wherethe first bearing 260 is located.

The compressor 245 has three chambers 247, 248 and 249, each chamberhaving a gas inlet and a gas outlet to allow gas flow to enter and toexit the respective chamber. The gas may be air. The shafts 265 and 265′penetrate through the chambers. Impellers 257, 258 and 259 are mountedon the shafts in chambers 247, 248 and 249, respectively. The impellers257 and 258 are low pressure components and may be open impeller type.The impeller 259 is a high pressure component and may be of closedimpeller type. The low pressure components 257 and 258 may be axiallystacked, while the high pressure component 259 may be either stackedtype or shrunk fit onto shaft 265′. The shafts 265 and 265′ and theimpellers 257, 258 and 259 are axially connected to constitute the rotorof compressor 245.

The gas flow enters the first chamber 247 of the compressor 245 having afirst input pressure (e.g., of about 0.97 bar) and a first inputtemperature (e.g., of about 41.5° C.), and is output having a firstoutput pressure (e.g., of about 3.20 bar) higher than the first inputpressure, and a first output temperature (e.g., of about 187° C.) higherthan the first input temperature.

The output gas is then cooled (i.e., a first cooling outside thecompressor) and input into the second chamber 248 of the compressor 245having a second input pressure (e.g., 2.85 bar) and a second inputtemperature (e.g., of about 40° C.). Inside the second chamber 248, thegas is compressed to be output having a second output pressure (e.g., ofabout 7.80 bar) higher than the second input pressure, and a secondoutput temperature (e.g., of about 160° C.) higher than the second inputtemperature.

The gas flow is then cooled again (i.e., a second cooling outside thecompressor) and input into the third chamber 249 of the compressor 245having a third input pressure (e.g., 7.50 bar) and a second inputtemperature (e.g., of about 40° C.). Inside the third chamber 249, thegas is compressed to be output having a third output pressure (e.g., ofabout 20.8 bar) higher than the third input pressure, and a third outputtemperature (e.g., of about 166° C.) higher than the third inputtemperature.

A schematic diagram of a turbo-compressor/generator train 300, accordingto another exemplary embodiment, is illustrated in FIG. 3. Theturbo-compressor/generator train 300 includes a gas turbine 310, agenerator 320, a gear box 330, and a single compressor 345 with multiplecooling. The gas turbine 310, the generator 320, and the gear box 330may be similar to the gas turbine 110, the generator 120, and the gearbox 130 in the conventional turbo-compressor/generator train 100.

Similar to compressor 245, the compressor 345 is a high pressure ratiocompressor with multiple intercooling that may achieve a ratio of theoutput pressure to the input pressure over 20. The compressor 345 hasthree chambers 347, 348 and 349, with impellers 357, 358 and 359 mountedon the shaft 365 therein. The gas flow is compressed inside the chambers347, 348 and 349 in a manner similar to the manner described relative tocompressor 245.

The shaft 365 of compressor 345 may be supported by plural bearings. Afirst bearing 360 is located outside the compressor 345, at a side ofthe casing 346 of the compressor 345 toward the gear box 330. Differentfrom compressor 245, a second bearing 380 is located inside compressor345 between chamber 347 and chamber 348 thereof. This arrangement of thebearings allows a higher rotation of the shaft 365, than of shafts 265,265′, for example, up to 7000 RPM.

Conventional turbo-compressor/generator trains may be retrofitted byreplacing the two compressors with a single high pressure ratiocompressor with multiple intercooling. FIG. 4 is a flowchartillustrating a method 400 for retrofitting a conventionalturbo-compressor/generator train, according to an exemplary embodiment.The method 400 includes removing at least two compressors from theconventional turbo-compressor/generator train, at S410, and adding asingle high pressure ratio compressor with multiple intercooling, at5420. The single compressor is configured to achieve the samecompression as the removed compressors.

The single compressor may have multiple chambers inside which a gas flowis compressed. For example, the single compressor may have threechambers. The compressed gas flow is output from two of the chambers tobe cooled outside the compressor before being directed into the nextchamber.

The method may further include adding at least two bearings to support ashaft of the single compressor. One of the added bearings may be locatedoutside the casing of the single compressor, at a side thereof towardthe gear box of the turbo-compressor/generator train. In one embodimenta second bearing may also be located outside the casing of the singlecompressor, at the opposite side of the casing relative to the sidewhere the first bearing is located. In another embodiment, a secondbearing may be located inside the casing of the single compressor. Forexample, the second bearing may be located between chambers of thecompressor.

The disclosed exemplary embodiments provide a turbo-compressor/generatortrain including a single high pressure compressor with multiple coolingand related methods. It should be understood that this description isnot intended to limit the invention. On the contrary, the exemplaryembodiments are intended to cover alternatives, modifications andequivalents, which are included in the spirit and scope of the inventionas defined by the appended claims. Further, in the detailed descriptionof the exemplary embodiments, numerous specific details are set forth inorder to provide a comprehensive understanding of the claimed invention.However, one skilled in the art would understand that variousembodiments may be practiced without such specific details.

Although the features and elements of the present exemplary embodimentsare described in the embodiments in particular combinations, eachfeature or element can be used alone without the other features andelements of the embodiments or in various combinations with or withoutother features and elements disclosed herein.

This written description uses examples of the subject matter disclosedto enable any person skilled in the art to practice the same, includingmaking and using any devices or systems and performing any incorporatedmethods. The patentable scope of the subject matter is defined by theclaims, and may include other examples that occur to those skilled inthe art. Such other examples are intended to be within the scope of theclaims.

What is claimed is:
 1. A high pressure ratio compressor with multipleintercooling used in a turbo-compressor/generator train, the compressorcomprising: a casing with plural chambers, each chamber comprising a gasinlet and a gas outlet to allow gas flow to be input into and to beoutput from the respective chamber; one or more shafts penetratinginside the chambers; and impellers mounted on the one or more shafts,inside the chambers, respectively, wherein a gas flow is successivelycompressed in each of the chambers, and is cooled outside the casingwhen transferring from one chamber to a next chamber among the pluralchambers.
 2. The compressor of claim 1, wherein the compressor isconfigured to achieve a compression ratio over 20, for a gas flow around220000 kg/h.
 3. The compressor of claim 1, further comprising pluralbearings supporting the shaft, wherein one of the plural bearings islocated on the shaft outside the casing, at a side of the casing towardsa gear box of the turbo-compressor/generator train.
 4. The compressor ofclaim 3, wherein one of the plural bearings is located on the shaftoutside the casing, at an opposite side of the casing relative to theside of the casing towards the gear box.
 5. The compressor of claim 3,wherein one of the plural bearings is located on the shaft inside thecasing, near a wall separating chambers of the compressor.
 6. Thecompressor of claim 5, wherein the chambers are arranged in an ordercorresponding to an output pressure of the gas flow, the another one ofthe plural bearings being located near the wall separating lowerpressure chambers of the compressor, and the one of the plural bearingsbeing located near a chamber corresponding to the highest outputpressure.
 7. The compressor of claim 1, wherein the chambers comprisethree chambers, and pressure of the gas flow output from one chamberdrops about 10% while being cooled outside the casing before being inputinto the next chamber.
 8. The compressor of claim 1, wherein thecompressor is configured to meet at least one of the followingconditions: temperatures of the gas flow input in each of the chambersis around 40° C.; a ratio of pressure of the gas flow output from eachchamber to pressure of the gas flow input in the respective chamber isbetween 2.5 and 3.5; an input pressure of the gas flow input in a firstchamber of the compressor is about 1 bar; an output pressure of the gasflow output from the compressor is about 20.8 bar; and a rotation speedof the one or more shafts is between 5000-7000 RPM.
 9. (canceled)
 10. Aturbo-compressor/generator train, comprising: a high pressure ratiocompressor with multiple intercooling, compressor comprising: a casingwith plural chambers, each chamber comprising a gas inlet and a gasoutlet to allow gas flow be input into and to be output from therespective chamber; one or more shafts penetrating inside the chambers;and impellers mounted on the one or more shafts inside the chambers,respectively, wherein a gas flow is successively compressed in each ofthe chambers, and is cooled outside the casing when transferring fromone chamber to a next chamber among the plural chambers.
 11. A method ofretrofitting a conventional turbo-compressor/generator train, the methodcomprising: removing at least two compressors from the conventionalturbo-compressor/generator train; and adding a single high pressureratio compressor with multiple intercooling, wherein the singlecompressor is configured to achieve the same compression as the removedcompressors.
 12. The compressor of claim 3, wherein the compressor isconfigured to achieve a compression ratio over 20, for a gas flow around220000 kg/h.
 13. The compressor of claim 4, wherein the compressor isconfigured to achieve a compression ratio over 20, for a gas flow around220000 kg/h.
 14. The compressor of claim 5, wherein the compressor isconfigured to achieve a compression ratio over 20, for a gas flow around220000 kg/h.
 15. The compressor of claim 7, wherein the compressor isconfigured to achieve a compression ratio over 20, for a gas flow around220000 kg/h.
 16. The compressor of claim 8, wherein the compressor isconfigured to achieve a compression ratio over 20, for a gas flow around220000 kg/h.
 17. The compressor of claim 3, wherein the chamberscomprise three chambers, and pressure of the gas flow output from onechamber drops about 10% while being cooled outside the casing beforebeing input into the next chamber.
 18. The compressor of claim 12,wherein the chambers comprise three chambers, and pressure of the gasflow output from one chamber drops about 10% while being cooled outsidethe casing before being input into the next chamber.
 19. The compressorof claim 18, wherein the compressor is configured to meet at least oneof the following conditions: temperatures of the gas flow input in eachof the chambers is around 40° C.; a ratio of pressure of the gas flowoutput from each chamber to pressure of the gas flow input in therespective chamber is between 2.5 and 3.5; an input pressure of the gasflow input in a first chamber of the compressor is about 1 bar; anoutput pressure of the gas flow output from the compressor is about 20.8bar; and a rotation speed of the one or more shafts is between 5000-7000RPM.
 20. The compressor of claim 3, wherein the compressor is configuredto meet at least one of the following conditions: temperatures of thegas flow input in each of the chambers is around 40° C.; a ratio ofpressure of the gas flow output from each chamber to pressure of the gasflow input in the respective chamber is between 2.5 and 3.5; an inputpressure of the gas flow input in a first chamber of the compressor isabout 1 bar; an output pressure of the gas flow output from thecompressor is about 20.8 bar; and a rotation speed of the one or moreshafts is between 5000-7000 RPM.